Background: Intermittent fasting (IF) and calorie restriction (CR) have anti-inflammatory effects, although whether one is superior in reducing the inflammatory burden of adults at risk of type 2 diabetes (T2D) remains unclear.
Objective: This sub-study aimed to compare the effects of IF plus early time-restricted eating (iTRE) to CR and a standard care (SC) group on inflammatory biomarkers.
Methods: Adults (N = 209, 58 ± 10 years, 34.8 ± 4.7 kg/m2) at increased risk of developing T2D were randomized to one of three groups (2:2:1): iTRE (30% energy requirements between 0800 and 1200 hours and followed by a 20-hour fasting period on three non-consecutive days per week, and ad libitum eating on other days); CR (70% of energy requirements daily, without time prescription); or SC (health booklet). This randomized controlled trial provided nutritional support to participants in the iTRE and CR arms for 6 months. In plasma, inflammatory biomarkers (C-reactive protein [CRP], tumour necrosis factor α [TNF-α], interleukin-6 [IL-6] and interferon-ɣ [IFNɣ]) were measured at baseline and month 6 in a subgroup of participants with weight loss above median (CR: N=32, iTRE: N=35) or below median (SC: N=18). Mixed linear models were used to assess the treatment effect with group, visit and group-by-visit interaction as fixed factors and subject as random factor after adjusting for baseline, sex and AUSDRISK score.
Results: Weight loss was similar between iTRE and CR at month 6 (-10.6±0.85% vs -10.3±0.70%, p=0.671). There was no change in weight in the SC group (-0.13±0.51%, p=0.834). A visit effect was detected in CRP and TNF-α levels, which were reduced at month 6 (CRP: -1.36±0.47mg/dL, p<0.001; TNF-α: -0.082±0.03pg/mL, p=0.025). There were no group or group-by-visit effects for any inflammatory marker.
Conclusions: There was no clear advantage to either diet in reducing inflammation in adults at risk of T2D.